Saving multiple data frames and return them from a function

Question

I have a snipet of code that reads all the files with a specific extension from a folder and each dataset is saved as a data frame with default name. The code was working fine untill I turned it into a function. The function runs fine but is not returning anything. I wanted to ask if there is a way of having this function return all the data frames?

The function is below:

library(devtools); install_github(BioStatMatt/sas7bdat.parso)

ReadFiles <- function()
  {
  path <- "C:/Users/abc/Desktop/abc/test/"
  files <- list.files(path=path, pattern="*.sas7bdat")
    for(file in files)
      {
        perpos <- which(strsplit(file, "")[[1]]==".")
        assign(
        gsub(" ","",substr(file, 1, perpos-1)), 
        read.sas7bdat.parso(paste(path,file,sep="")))
      }
  }

I will appreciate some guidance onto how I can make this function work.

Thanks.

Answer 1

Your function is indeed not returning anything. To resolve this, you could save the dataframes that you generate inside the for loop in a list and then return this resultlist with all the dataframes in it.

Conceptually, it will look something like this:

ReadFiles <- function()
{
  files <- # fetch the files
  resultList <- vector("list",length(files))
  for(i in seq(1,length(files))) # process each file
  {
    file <- files[i]
    resultList[[i]] <- # fetch your data(frame)
  }
  resultList # Return the result!
}

results <- readFiles()
# You can now access your individual dataframes like this:
dataFrame1 <- results[[1]]
# Or merge them all together if you like:
combinedDataFrame <- do.call("rbind",results)